Coronets and Belvederes are hard to find, I’ve not seen any for a doable price , but at least you can get parts. A four door Dart or Valant could be a reasonably priced A body option, though you really have to beef up the suspension f yu upgrade the 225 or 273 that came stock in the earlier models.
I drive by a farm house every day when I go to work,the guy has 3 Belvederes sitting there.